450 PROFESSOR GEIKIE ON THE 
zone of white sandstone. The united depth of this igneous and aqueous series 
is at least 400 feet. It is succeeded above by about 600 feet of porphyrite in 
admirably well-defined beds or flows, which are separated as a rule, not by 
intercalations of tuff, but by the slagey vesicular surfaces between the successive 
sheets.* Mr B. N. Peacu, in the course of the Geological Survey of this district, 
ascertained that while the volcanic masses attam a depth of about 1000 feet at 
Kilsyth, and swell out to far more than that thickness as they are followed 
westwards, they thin away rapidly eastward until about a mile north of Stirling, 
or 13 miles from Kilsyth, they disappear altogether, and the Calciferous Sand- 
stone series closes up without any igneous intercalation. Nothing could show 
more strikingly the remarkably local character of the volcanic phenomena with 
which we are here concerned. 
The second part of the volcanic history of the Stirlingshire district is 
represented by the numerous thick sheets of dolerite and other pyroxenic 
rocks which extend from the neighbourhood of Kilsyth, round the base of the © 
Campsie Fells to beyond Stirling. These masses have been intruded among 
the Carboniferous Limestone series of strata, probably at a time before the 
consolidation and disturbance of these strata, seeing that they have been faulted 
and bent together with them.t They belong to an extensive belt of intruded 
matter which, keepmg not far from the base of the Carboniferous Limestone 
series, extends to near the east end of the long county of Fife, and forms in its 
course the prominent eminences of the Cleish, Lomond, and Ceres Hills. We 
cannot be quite sure of the dates of these masses, some of them no doubt 
belong to the voleanic phenomena of the Carboniferous period, but some may 
be post-Carboniferous and even Tertiary. 
5. West of Fife District—F¥or the sake of convenience, the volcanic rocks 
of the county of Fife (leaving out of account at present the intrusive 
sheets) may be grouped in two districts, separated from each other by the 
Dysart and Leven coal-fields, in which hardly any volcanic rocks occur. 
In the west of Fife we are presented with almost a counterpart of the 
features of West Lothian. From about the time of the Burdie House Limestone, _ 
until a considerable part of the upper or coal-bearing part of the Carboniferous 
Limestone series had been deposited, volcanic eruptions continued to take place 
tuff remain there among the surrounding strata, to mark the sites of some of 
the vents. Another and more extensive group lay about six or eight miles 
eastward in the neighbourhood of Burntisland. In this interesting little areawe 
meet with a series of tuffs and lavas occupying nearly the whole of the inter 
* B. N. Pxacu, in Explanation to Sheet 31, “Geo. Surv. Scotland,” p. 15. 
+ B. N. Praon, op. cit. p. 45. 
